CN111934296A - Relay protection method of flexible passing neutral section device - Google Patents

Abstract

The invention discloses a relay protection method of a flexible over-phase device. One output end of the flexible over-phase device is connected to the power supply arm B through the circuit breaker QF1, and the other output end is connected to the neutral section through the circuit breaker QF2; the neutral section is located between the power supply arm B and the power supply arm A. The invention realizes the reliable protection of the fault of the flexible over-phase device through the cooperation of the current quick-break protection and the overcurrent protection of the second harmonic blocking, realizes the reliable protection of the neutral section failure through the low-voltage protection, and realizes the protection of the train rush through the voltage difference protection. Reliable protection against split-phase faults.

Description

A kind of relay protection method of flexible over-phase device

technical field

The invention relates to the technical field of electrified railway power supply, in particular to a relay protection method of a flexible over-phase split device.

Background technique

With the continuous development of the railway system towards high speed and heavy load, automatic over-phase technology is becoming increasingly important. For general ground switch switching or vehicle-mounted over-phase switching technology, there are shortcomings such as low switch life, over-voltage during over-phase switching, and low reliability. In contrast, the automatic phase-over-phase technology using the flexible over-phase over-phase device can make the train uninterrupted power supply, flexible and non-impact through electrical phase separation. At present, the research on flexible over-phase technology mainly focuses on the flexible over-phase scheme, control strategy, etc., and there is no complete relay protection method for flexible over-phase devices. The relay protection method of the flexible over-phase device has particularity. In addition to the need to protect the fault of the flexible over-phase device itself, it should also be able to protect the internal fault of the over-phase device or the secondary faults such as train rushing points after exiting, as well as the train's damage. A cross-section fault caused by the pantograph connecting adjacent isolated supply sections.

SUMMARY OF THE INVENTION

The invention discloses a relay protection method for a flexible over-phase device, which can realize reliable protection for the internal fault of the flexible over-phase device, the neutral section fault and the live train inrush and split-phase fault, thereby ensuring the safe operation of power supply equipment and over-phase trains.

The protection method of the internal fault of the flexible over-phase device, the technical scheme is as follows:

且I₁₁≥I_set2，则T_set2之后，跳QF1和QF2；其中，I₁₁表示所述柔性过分相装置的输入电流

的基波电流有效值，I₁₂表示

的2次谐波电流有效值；I_set1表示电流速断整定值，I_set2表示过电流整定值；K_2set表示2次谐波闭锁整定值；T_set1表示电流速断保护延时定值，T_set2表示过电流保护延时定值。A relay protection method for a flexible over-phase device, wherein one output end of the flexible over-phase device is connected to a power supply arm B through a circuit breaker QF1, and the other output end is connected to a neutral section through a circuit breaker QF2; the neutral section is located at Between power supply arm B and power supply arm A; if I ₁₁ ≥I _set1 , then after T _set1 , jump to QF1 and QF2; or, if

And I ₁₁ ≥I _set2 , then after T _set2 , jump QF1 and QF2; wherein, I ₁₁ represents the input current of the flexible over-phase device

The rms value of the fundamental current, I ₁₂ represents

The rms value of the second harmonic current; I _set1 means the current quick-break setting value, I _set2 means the overcurrent setting value; K _2set means the second harmonic blocking setting value; T _set1 means the current quick-break protection delay setting value, T _set2 means Overcurrent protection delay setting.

The protection method of neutral segment fault, its technical scheme is as follows:

的基波电压有效值，U_B1表示供电臂B电压

的基波电压有效值；U_set1表示低压整定值，U_set2表示有压整定值；T_set3表示低压保护延时定值。A relay protection method for a flexible over-phase device, wherein one output end of the flexible over-phase device is connected to a power supply arm B through a circuit breaker QF1, and the other output end is connected to a neutral section through a circuit breaker QF2; the neutral section is located at Between power supply arm B and power supply arm A; if QF1 is in position, QF2 is in position, U _N1 ≤ U _set1 and U _B1 ≥ U _set2 , then after T _set3 , jump to QF2; among them, U _N1 represents the neutral voltage

The rms value of the fundamental wave voltage, U _B1 represents the voltage of the power supply arm B

The effective value of the fundamental wave voltage; U _set1 represents the low voltage setting value, U _set2 represents the voltage setting value; T _set3 represents the low voltage protection delay setting value.

The protection method of the train's live inrush and split-phase fault includes AN voltage difference protection and BN voltage difference protection. The technical solutions are as follows:

则T_set4之后，跳QF2并远跳供电臂A的所有断路器；其中，U_AN1表示供电臂A与中性段之间电压差的基波电压有效值，U_AN3表示供电臂A与中性段之间电压差的3次谐波有效值；U_set3表示下限电压整定值，U_set4表示上限电压整定值；K_3set表示电压3次谐波含量整定值；T_set4表示电压差保护延时定值。AN voltage difference protection: a relay protection method for a flexible over-phase device, one output end of the flexible over-phase device is connected to the power supply arm B through the circuit breaker QF1, and the other output end is connected to the neutral section through the circuit breaker QF2 ; The neutral segment is located between the power supply arm B and the power supply arm A; such as U _set3 ≤U _AN1 ≤U _set4 and

Then after T _set4 , jump QF2 and jump all the circuit breakers of the power supply arm A; among them, U _AN1 represents the fundamental voltage RMS value of the voltage difference between the power supply arm A and the neutral section, and U _AN3 represents the power supply arm A and the neutral section. The effective value of the 3rd harmonic of the voltage difference between the sections; U _set3 represents the lower limit voltage setting value, U _set4 represents the upper limit voltage setting value; K _3set represents the voltage 3rd harmonic content setting value; T _set4 represents the voltage difference protection delay setting value.

则T_set4之后，远跳供电臂B的所有断路器；其中，U_BN1表示供电臂B与中性段之间电压差的基波电压有效值，U_BN3表示供电臂B与中性段之间电压差的3次谐波有效值；U_set3表示下限电压整定值，U_set4表示上限电压整定值；K_3set表示电压3次谐波含量整定值；T_set4表示电压差保护延时定值。BN voltage difference protection: a relay protection method for a flexible over-phase device, one output end of the flexible over-phase device is connected to the power supply arm B through the circuit breaker QF1, and the other output end is connected to the neutral section through the circuit breaker QF2 ; The neutral segment is located between the power supply arm B and the power supply arm A; such as U _set3 ≤ U _BN1 ≤ U _set4 and

Then after T _set4 , all circuit breakers of power supply arm B are far tripped; among them, U _BN1 represents the fundamental voltage RMS value of the voltage difference between the power supply arm B and the neutral segment, and U _BN3 represents the difference between the power supply arm B and the neutral segment The effective value of the 3rd harmonic of the voltage difference; U _set3 represents the lower limit voltage setting value, U _set4 represents the upper limit voltage setting value; K _3set represents the voltage 3rd harmonic content setting value; T _set4 represents the voltage difference protection delay setting value.

The beneficial effect of the present invention is that,

(1) Reliable protection of flexible over-phase device faults is achieved through the coordination of current quick-break protection and second harmonic blocking over-current protection.

(2) Reliable protection for neutral segment fault is realized through low voltage protection.

(3) Reliable protection for train inrush and split phase fault is realized through voltage difference protection.

Description of drawings

Figure 1 is a schematic diagram of the flexible transition phase system scheme.

Figure 2 is a schematic diagram of the neutral section voltage synthesis.

Figure 3 is a block diagram of the current quick-break protection principle.

Figure 4 is a block diagram of the second harmonic blocking overcurrent protection principle.

Figure 5 is a block diagram of the low-voltage protection principle.

Fig. 6 is a polygonal impedance characteristic diagram of distance protection.

Figure 7 is a block diagram of the AN voltage difference protection principle.

Figure 8 is a block diagram of the BN voltage difference protection principle.

FIG. 9 is a schematic diagram of a flexible over-phase device installed in a single-line direct supply partition.

Figure 10 is a schematic diagram of the installation of the flexible over-phase device in the double-line direct supply partition.

Figure 11 is a schematic diagram of the flexible over-phase device installed in the I-type fully parallel AT power supply partition.

Figure 12 is a schematic diagram of the flexible over-phase device installed in the type II fully parallel AT power supply partition.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings.

1. Flexible over-phase system scheme

The flexible over-phase device is bridged between the power supply arm and the neutral section on one side to form a flexible over-phase system, the scheme of which is shown in Figure 1. In Figure 1, the flexible over-phase device is composed of isolation transformers T1, T2 and back-to-back converters; QF1, QF2 represent circuit breakers; J1, J2, J3, J4 represent axle counting sensors, according to the axle logarithmic signals generated by J1 and J2 It can judge whether there is a train and the direction of the train in Section A. According to the logarithmic signals of the axles generated by J2 and J3, it can judge whether there is a train and the running direction of the trains in Section N. According to the logarithmic signals of the axles generated by J3 and J4, it can judge whether there is a train in Section B. Train and train direction.

由供电臂B的电压

和背靠背变流器经T2升压后的电压

叠加而成，即

如图2所示。

根据列车所在位置和行驶方向调节，可实现中性段电压

由

柔性过渡至

从而使得列车过分相时不存在供电死区。Neutral voltage

The voltage supplied by arm B

and the voltage of the back-to-back converter boosted by T2

superimposed, that is

as shown in picture 2.

According to the position of the train and the direction of travel, the neutral voltage can be achieved

Depend on

Flexible transition to

Therefore, there is no power supply dead zone when the train is over-phased.

When the train travels from the power supply arm A to the power supply arm B, the basic sequence of the output voltage of the flexible over-phase splitting device is:

使

(1) When it is detected that the train has just entered the A section, the flexible over-phase device adjusts

Make

为控制目标渐进调幅移相；(2) When it is detected that the train enters the N section from the A section, the flexible over-phase device will

Progressive amplitude modulation and phase shift for the control target;

(3) Complete the phase shift before the train enters section B, so that

(4) When the train leaves section B, the flexible over-phase device returns to the standby state.

When the train travels from the power supply arm B to the power supply arm A, the output voltage sequence is opposite to the above process, and will not be repeated here.

2. Relay protection method of flexible over-phase device

(1) Protection method for internal fault of flexible over-phase device

In order to protect the internal fault of the flexible over-phase device, the current quick-break and second harmonic blocking over-current protection are set. Once the criterion is met, QF1 and QF2 are disconnected to exit the flexible over-phase device. The protection principle diagrams are shown in Figure 3 and Figure 4 respectively. Show.

的基波电流有效值和2次谐波电流有效值；I_set1表示电流速断整定值，按躲过T1和T2最大励磁涌流整定；K_2set表示2次谐波闭锁整定值，一般取0.15；I_set2表示过电流整定值，按躲过最大负荷电流整定；T_set1、T_set2表示电流速断和过电流保护延时定值。In Fig. 3 and Fig. 4, I ₁₁ and I ₁₂ respectively represent

The fundamental wave current effective value and the second harmonic current effective value; I _set1 represents the current quick-break setting value, which is set according to the maximum excitation inrush current that escapes T1 and T2; K _2set represents the second harmonic blocking setting value, generally taken as 0.15; I _set2 represents the overcurrent setting value, which is set according to avoiding the maximum load current; T _set1 and T _set2 represent the current quick-break and over-current protection delay setting values.

(2) Protection method of neutral segment fault

When a short circuit fault occurs in the neutral section, the voltage in the neutral section is very low. The flexible over-phase device converter will quickly block the IGBT rectification pulse in microseconds due to undervoltage. Therefore, the short circuit is that the power supply arm B short-circuits the neutral section through the transformer T2, the impedance is large, the current is small, and the voltage of the power supply arm B is still high. In order to protect the neutral segment fault, low-voltage protection is set up, and the protection principle diagram is shown in Figure 5.

的基波电压有效值，U_set1表示低压整定值，按小于牵引网最低运行电压整定；U_set2表示有压整定值，按大于牵引网最低运行电压整定；T_set3表示低压保护延时定值。In Fig. 5, U _N1 and U _B1 respectively represent

The effective value of the fundamental wave voltage, U _set1 represents the low voltage setting value, which is set according to less than the minimum operating voltage of the traction network; U _set2 represents the voltage setting value, which is set according to the minimum operating voltage of the traction network; T _set3 represents the low-voltage protection delay setting value.

(3) Protection methods for cross-section faults

为涌流偏移角；

为容性偏移角；

为线路阻抗角。电阻整定值按躲过最小负荷电阻整定，电抗按躲过供电臂A的最大短路电抗整定。If a short-circuit fault occurs in the power supply arm A, when a train runs to the transition area between the power supply arm A and the neutral section, the train pantograph will bridge the power supply arm A and the neutral section, resulting in a cross-section fault. If the fault is a near-end fault, the neutral segment voltage will be pulled down, and the low-voltage protection shown in Figure 5 can reliably act to cut off. If the fault is a remote fault, the voltage of the neutral section may not drop very much, and the flexible over-phase device will provide short-circuit current to the fault point. For this situation, set distance protection for QF2. The distance protection adopts polygonal action characteristics as shown in Figure 6. In Figure 6, R _set is the setting value of the resistance side; X _set is the setting value of the reactance side;

is the inrush current offset angle;

is the capacitive offset angle;

is the line impedance angle. The resistance setting value is set according to avoiding the minimum load resistance, and the reactance is set according to the maximum short-circuit reactance that avoids the power supply arm A.

(4) The protection method of the train's electrified inrush and split-phase fault

When the flexible over-phase splitting device fails or is out of maintenance, it may happen that the train enters the neutral section without electricity from the live power supply arm A or B, resulting in the breakdown of the air gap between the power supply arm and the neutral section, resulting in arcing . The arc can burn stably for a long time, which will lead to the burning of load-bearing cables and contact wires. At this time, the voltage of the power supply arm is still very high, the current is the load current, and the measured impedance value is also very large, so the distance protection and current protection cannot operate correctly. For this reason, the phase-to-phase voltage difference protection is set up by taking advantage of the high content of the third harmonic of the arc voltage, as shown in Figure 7 and Figure 8, respectively.

In Fig. 7 and Fig. 8, U _AN1 and U _AN3 represent the fundamental RMS value and the third harmonic RMS value of the voltage difference between the power supply arm A and the neutral section; U _BN1 , U _BN3 represent the power supply arm B and the neutral section The fundamental wave RMS and the third harmonic RMS of the voltage difference between them; U _set3 represents the lower limit voltage setting value, which can generally be set to 0.1-1kV; U _set4 represents the upper limit voltage setting value, which can generally be set to 4-8kV; K _3set represents the set value of the third harmonic content of the voltage, generally taking 0.2-0.3; T _set4 represents the set value of the voltage difference protection delay.

In the event of an arc between the supply arm and the electrical split, all circuit breakers associated with the arc branch must be used. Therefore, for the AN voltage difference protection in Figure 7, it is necessary to trip QF2 and remotely jump all circuit breakers on the power supply arm A through communication; for the BN voltage difference protection in Figure 8, it is necessary to remotely jump the power supply arm B through communication. All circuit breakers.

The effects obtained by the invention are: through the coordination of the current quick-break protection and the overcurrent protection of the second harmonic blocking, the reliable protection of the fault of the flexible over-phase device is realized; the reliable protection of the neutral section fault is realized through the low-voltage protection; The cooperation of voltage protection and impedance protection realizes reliable protection for cross-section faults; and through voltage difference protection, it realizes reliable protection for train breaking and splitting faults.

Specific examples are as follows:

1. The flexible over-phase device is installed in the single-line direct supply substation

As shown in Figure 9, when the traction power supply system is in the single-line direct supply mode, the method of the present invention switches off QF1 and QF2 when the internal fault of the flexible over-phase device is faulty, and the method of the present invention switches off QF2 for the neutral section fault and its cross-section fault. When the train travels from the power supply arm A to the neutral section, a phase breakout fault occurs, and the method of the present invention jumps off QF2 and jumps the 1QF of the substation 1 far away. The method of the present invention jumps the 2QF of the substation 2 far away.

2. The flexible over-phase device is installed in the double-line direct supply substation

As shown in Figure 10, when the traction power supply system is in the mode of double-line direct supply, the method of the present invention trips QF1 and QF2 when the internal fault of the flexible over-phase device 1 occurs, and the method of the present invention skips the fault of the neutral section 1 and its cross-section fault. Open QF2, when the train travels from the power supply arm A to the neutral section and produces a phase breakout failure The method of the present invention jumps the 8QF of the substation and the 2QF of the substation 2 far away when the split-phase fault occurs during the segment driving. When there is an internal fault of the flexible over-phase device 2, the method of the present invention will skip QF3 and QF4, the neutral section 2 fault and its cross-section fault, and the method of the present invention will skip QF4. When the phase fault occurs, the method of the present invention jumps off QF4 and the 7QF of the substation and the 3QF of the substation 1. When the train travels from the power supply arm B to the neutral section, a split-phase fault occurs. The method of the present invention jumps the 8QF of the substation. and 4QF of Substation 2.

3. The flexible over-phase device is installed in the I-type full-parallel AT power supply substation

As shown in Figure 11, when the traction power supply system is the I-type full-parallel AT power supply mode, the method of the present invention trips QF1 and QF2 when the internal fault of the flexible over-phase device 1 occurs, and the neutral section 1 fault and its cross section fault are The inventive method skips QF2. When the train travels from the power supply arm A to the neutral section, a phase-intrusion fault occurs. The inventive method skips the QF2 and skips 1QF, 3QF, and 5QF. When the train travels from the power supply arm B to the neutral section, the The method of the present invention jumps 2QF, 4QF and 6QF far away when the split-phase fault occurs. When there is an internal fault of the flexible over-phase device 2, the method of the present invention will skip QF3 and QF4, the neutral section 2 fault and its cross-section fault, and the method of the present invention will skip QF4. When a phase fault occurs, the method of the present invention jumps off QF4 and jumps 7QF, 3QF, and 5QF.

4. The flexible over-phase device is installed in the type II full-parallel AT power supply substation

As shown in Figure 12, when the traction power supply system is the type II full-parallel AT power supply mode, the method of the present invention trips QF1 and QF2 when the internal fault of the flexible over-phase device 1 occurs, and the neutral section 1 fault and its cross section fault The inventive method skips QF2. When the train travels from the power supply arm A to the neutral section, a phase-intrusion fault occurs. The inventive method skips the QF2 and skips 1QF, 3QF, and 5QF. When the train travels from the power supply arm B to the neutral section, the The method of the present invention jumps 2QF, 4QF and 6QF far away when the split-phase fault occurs. When the internal fault of the flexible over-phase device 2 occurs, the method of the present invention skips QF3 and QF4, the neutral section 2 fault and its cross-section fault, and the method of the present invention skips QF4. When the phase fault occurs, the method of the present invention jumps off QF4 and jumps 7QF, 9QF, 11QF far.

Claims (4)

1. A relay protection method for a flexible over-phase device, characterized in that one output end of the flexible over-phase device is connected to the power supply arm B through the circuit breaker QF1, and the other output end is connected to the neutral through the circuit breaker QF2. segment; the neutral segment is located between the power supply arm B and the power supply arm A; If I ₁₁ ≥I _set1 , then after T _set1 , jump to QF1 and QF2; or, like

And I ₁₁ ≥I _set2 , then after T _set2 , jump to QF1 and QF2; Wherein, I ₁₁ represents the input current of the flexible over-phase device

The rms value of the fundamental current, I ₁₂ represents

The rms value of the second harmonic current; I _set1 means the current quick-break setting value, I _set2 means the overcurrent setting value; K _2set means the second harmonic blocking setting value; T _set1 means the current quick-break protection delay setting value, T _set2 means Overcurrent protection delay setting. 2. A relay protection method for a flexible over-phase device, characterized in that one output end of the flexible over-phase device is connected to the power supply arm B through the circuit breaker QF1, and the other output end is connected to the neutral through the circuit breaker QF2. segment; the neutral segment is located between the power supply arm B and the power supply arm A; If QF1 is combined, QF2 is combined, U _N1 ≤U _set1 and U _B1 ≥U _set2 , after T _set3 , jump to QF2; Among them, U _N1 represents the neutral voltage

The rms value of the fundamental wave voltage, U _B1 represents the voltage of the power supply arm B

The effective value of the fundamental wave voltage; U _set1 represents the low voltage setting value, U _set2 represents the voltage setting value; T _set3 represents the low voltage protection delay setting value. 3. A relay protection method for a flexible over-phase device, characterized in that one output end of the flexible over-phase device is connected to the power supply arm B through the circuit breaker QF1, and the other output end is connected to the neutral through the circuit breaker QF2. segment; the neutral segment is located between the power supply arm B and the power supply arm A; If U _set3 ≤U _AN1 ≤U _set4 and

Then after T _set4 , jump QF2 and jump all circuit breakers of power supply arm A; Among them, U _AN1 represents the fundamental voltage effective value of the voltage difference between the power supply arm A and the neutral segment, U _AN3 represents the 3rd harmonic effective value of the voltage difference between the power supply arm A and the neutral segment; U _set3 represents the lower limit voltage Setting value, U _set4 means the upper limit voltage setting value; K _3set means the setting value of the third harmonic content of the voltage; T _set4 means the voltage difference protection delay setting value. 4. A relay protection method for a flexible over-phase device, characterized in that one output end of the flexible over-phase device is connected to the power supply arm B through the circuit breaker QF1, and the other output end is connected to the neutral through the circuit breaker QF2. segment; the neutral segment is located between the power supply arm B and the power supply arm A; If U _set3 ≤U _BN1 ≤U _set4 and

Then after T _set4 , all circuit breakers of power supply arm B are far tripped; Among them, U _BN1 represents the fundamental voltage effective value of the voltage difference between the power supply arm B and the neutral segment, U _BN3 represents the 3rd harmonic effective value of the voltage difference between the power supply arm B and the neutral segment; U _set3 represents the lower limit voltage Setting value, U _set4 means the upper limit voltage setting value; K _3set means the setting value of the third harmonic content of the voltage; T _set4 means the voltage difference protection delay setting value.

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